The choice was made in CLJ-935 to consistently define whitespace as Character.isWhitespace() across trim, triml, and trimr. There are many possible ways to define "space" (at least two as we see here). If your trimming needs differ from the standard library, then you'll probably need to define your own functions to trim your data. You can still use Java interop to call String.trim() directly if that happens to match your needs.